Cryogenic balloon device with radiofrequency tip

ABSTRACT

An intravascular ablation device, including a flexible elongate body; an expandable element positioned on the elongate body; a radiofrequency or electroporation treatment segment located distally of the expandable element; a cryogenic coolant source in fluid communication with an interior of the expandable element; and a radiofrequency or electroporation energy source in communication with the radiofrequency or electroporation treatment segment.

CROSS-REFERENCE TO RELATED APPLICATION

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STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

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FIELD OF THE INVENTION

The present invention relates to a method and system for thermal tissuetreatment, and in particular, towards systems and methods of use thereoffor treating one or more tissue sites having varying geometries withvarying treatment modalities.

BACKGROUND OF THE INVENTION

Minimally invasive devices, such as catheters, are often employed forsurgical procedure, including those involving ablation, dilation, andthe like. In a particular situation, an ablation procedure may involvecreating a series of inter-connecting lesions in order to electricallyisolate tissue believed to be the source of an arrhythmia. During thecourse of such a procedure, a physician may employ several differentcatheters having variations in the geometry and/or dimensions of theablative element in order to produce the desired ablation pattern. Eachcatheter may have a unique geometry for creating a specific lesionpattern, with the multiple catheters being sequentially removed andreplaced to create the desired multiple lesions. Exchanging thesevarious catheters during a procedure can cause inaccuracies or movementin the placement and location of the distal tip with respect to thetissue to be ablated, and may further add to the time required toperform the desired treatment. These potential inaccuracies and extendedduration of the particular procedure increase the risk to the patientundergoing treatment. Accordingly, it would be desirable to provide asingle medical device having the ability to provide ablative patterns ofvarious shapes, without the need for additional catheters or the likehaving a single geometric orientation, and thus, limited in the abilityto provide multiple ablative patterns to one or more tissue sites.

SUMMARY OF THE INVENTION

The present invention advantageously provides a medical system havingmultiple, independently operable treatment regions providing the abilityto provide ablative patterns of various shapes. For example, a medicaldevice is disclosed, including an elongate catheter body; a cryogenictreatment region on the catheter body; and a radiofrequency orelectroporation treatment region distally of the cryogenic treatmentregion. The cryogenic treatment region may include an expandableelement, the radiofrequency treatment region may include a substantiallylinear thermal segment; and the cryogenic treatment region may beoperable independently from the radiofrequency treatment region. Thedevice may include a fluid flow path in fluid communication with thecryogenic treatment region; a cryogenic fluid source in fluidcommunication with the first fluid flow path; a radiofrequency signalsource or electrical-pulse generator coupled to the radiofrequency orelectroporation treatment region; and/or a sensor coupled to at leastone of the cryogenic treatment region or radiofrequency treatmentregion. The radiofrequency treatment region may be deflectableindependently of the cryogenic treatment region.

An intravascular ablation device is disclosed, including a flexibleelongate body; an expandable element positioned on the elongate body; aradiofrequency thermal segment located distally of the expandableelement; a cryogenic coolant source in fluid communication with aninterior of the expandable element; and a radiofrequency energy sourcein communication with the radiofrequency thermal segment. Theradiofrequency thermal segment may include an electrically-conductivedistal tip or a substantially linear, elongated electrically-conductivesegment.

A method of treating cardiac tissue is disclosed, including positioninga cryogenic treatment region of a medical device proximate a pulmonaryvein; ablating tissue proximate the pulmonary vein with the cryogenictreatment region; positioning a radiofrequency or electroporationtreatment region of the medical device proximate the pulmonary vein; andablating tissue proximate the pulmonary vein with theradiofrequency/electroporation treatment region. The cryogenic treatmentregion may include an expandable element, and positioning the expandableelement may include expanding the expandable element in the pulmonaryvein to substantially occlude the pulmonary vein. Ablating tissueproximate the pulmonary vein with the cryogenic treatment region mayinclude circulating a cryogenic fluid through the expandable element.The radiofrequency or electroporation treatment region may include anelectrode positioned distally of the cryogenic treatment region.Ablating tissue proximate the pulmonary vein with the cryogenictreatment region may include creating a first ablative treatmentpattern, and ablating tissue proximate the pulmonary vein with theradiofrequency/electroporation treatment region may include creating asecond ablative treatment pattern. The first ablative treatment patternmay include a substantially arcuate shape and/or the second ablativetreatment pattern may include a substantially focal shape, and the firstand second ablative treatment patterns may be substantially continuous.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present invention, and theattendant advantages and features thereof, will be more readilyunderstood by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings wherein:

FIG. 1 is an illustration of an example of a medical system constructedin accordance with the principles of the present disclosure;

FIG. 2 is an illustration of an exemplary use of the medical system ofFIG. 1; and

FIG. 3 is an additional illustration of an exemplary use of the medicalsystem of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

The present invention advantageously provides a medical system havingthe ability to provide ablative patterns of various shapes to treat oneor more targeted tissue sites. Referring now to the drawing figures inwhich like reference designations refer to like elements, an example ofa medical system constructed in accordance with principles of thepresent invention is shown in FIG. 1 and generally designated as “10.”The system 10 generally includes a medical device 12 that may be coupledto a control unit 14. The medical device 12 may include a medical probe,a catheter, or other instrument, and may generally include one or moretreatment regions for energetic or other therapeutic interaction betweenthe medical device 12 and a treatment site. The treatment region(s) maydeliver, for example, cryogenic therapy, radiofrequency energy,electroporation energy or other energetic transfer with a tissue area inproximity to the treatment region(s), including cardiac tissue.

The medical device 10 may include an elongate body 16 passable through apatient's vasculature and/or positionable proximate to a tissue regionfor diagnosis or treatment, such as a catheter, sheath, or intravascularintroducer. The elongate body 16 may define a proximal portion 18 and adistal portion 20, and may further include one or more lumens disposedwithin the elongate body 16 thereby providing mechanical, electrical,and/or fluid communication between the proximal portion of the elongatebody 16 and the distal portion of the elongate body 16. For example, theelongate body 16 may include a fluid delivery or injection lumen 22 andan exhaust lumen 24 defining a fluid flow path therethrough. Inaddition, the elongate body 16 may include a guide wire lumen 26 movablydisposed within and/or extending along at least a portion of the lengthof the elongate body 16 for over-the-wire applications. The guide wirelumen 26 may define a proximal end and a distal end, and the guide wirelumen 26 may be movably disposed within the elongate body 16 such thatthe distal end of the guide wire lumen 26 extends beyond and out of thedistal portion of the elongate body 16.

The medical device 12 may include one or more treatment regions forenergetic or other therapeutic interaction between the medical device 12and a treatment site. The treatment regions may deliver, for example,radiofrequency energy, cryogenic therapy, or the like. For example, thedevice may include a first treatment region 28 having a thermaltreatment element, such as an expandable membrane or balloon and/or oneor more electrodes or other thermally-transmissive components, at leastpartially disposed on the elongate catheter body. In a particularexample, the first treatment region 28 may include a firstexpandable/inflatable element or balloon 30 defining a proximal endcoupled to the distal portion 20 of the elongate body 16 of the medicaldevice 12, while further defining a distal end coupled to the distal endof the guide wire lumen 26. As such, due to the movable nature of theguide wire lumen 26 about the elongate body 16, any axial and/orlongitudinal movement of the guide wire lumen 26 may act to tension orloosen the first expandable element 30, i.e., extend or retract thefirst expandable element 30 from a lengthened state to a shortened stateduring an inflation or deflation thereof. In addition, the firstexpandable element 30 may have any of a myriad of shapes, and mayfurther include one or more material layers providing for punctureresistance, radiopacity, or the like. An interior chamber or regiondefined by the first expandable element 30 may be in communication withthe fluid injection and exhaust lumens of the medical device 12 asdescribed above, or may be fluidically isolated from either lumen.

The medical device 12 may further include a second expandable/inflatableelement or balloon 32 contained within or otherwise encompassed by thefirst expandable element 30 such that an interstitial region, envelopeor space 34 is defined therebetween. The second expandable element 32may be in communication with the fluid injection and exhaust lumens ofthe medical device 12 as described above, i.e., a fluid flow path mayprovide an inflation fluid or coolant, such as a cryogenic fluid or thelike, to the interior of the second expandable element 32. Further, theinterstitial region 34 may be in fluid communication with aninterstitial lumen 36 providing a fluid flow path or avenue separate andindependent from a fluid flow path delivering fluid or otherwise incommunication with an interior of the second expandable element 32. Thesecond pathway provides an alternate exhaust route for fluid that mayleak from the interior of the second expandable element into theinterstitial region or fluid entering the medical device 12 from theexterior. In particular, the isolation of the interstitial lumen 36 fromthe interior of the second expandable element 32 provides an alternateroute for fluid to circulate in the case of a rupture or leak of eitherthe first or second expandable elements, as well as allowing for theinjection or circulation of fluids within the interstitial regionindependently of fluids directed towards the second expandable element.Towards that end, the interstitial region 34 may be in fluidcommunication with a fluid source, a vacuum source, or the like separatefrom a fluid source, vacuum source or otherwise in fluid communicationwith the interior of the second expandable element. Alternatively, theinterstitial lumen 36 may be joined to or otherwise in fluidcommunication with the exhaust lumen 24 and the interior of the secondexpandable element 32 to provide a single exhaust or vacuum source forthe medical device 12.

Continuing to refer to FIG. 1, the medical device 12 may further includea second treatment region 38 located distally of the first treatmentregion 28. The second treatment region 38 is operable independently andseparately from the first treatment region 28, and may provide anablative treatment pattern different from a treatment pattern or shapeprovided by the first treatment region 28. In a particular example, thesecond treatment region 38 may provide for a “spot” or focal treatmentpattern through the use of radiofrequency energy. The second treatmentregion 38 may include one or more electrically conductive portions orelectrodes 40 coupled to a radiofrequency generator or power source. Forexample, the electrode(s) may be deposited or coupled to a distalportion of the elongate body 16 or guide wire lumen 26 distally of thefirst treatment region 28. The electrodes 40 may include variations intheir number, arrangement, configuration, or shape. The electrodes 40may be formed from metal, conductive polymers, conductive ink printing,or other electrically-conductive mediums.

The electrodes 40 may be customized to provide effective portionsselected among a variety of sizes and shapes for contacting or otherwiseassessing a tissue treatment area. The size, shape or length of theelectrodes 40 may be limited, for example, by covering a portion of theelectrode with an insulating material. The dimensions of the electrodes40 may thus have an optimized configured having sufficient size and ageometric arrangement to effectively treat or diagnose tissue, whileavoiding excessive surface area and minimizing reception of ‘noise’ orother signals.

The plurality of independently-controllable treatment regions providesthe ability to deliver varying therapeutic treatment patterns to one ormore locations. As described above, the first treatment region 28 mayinclude one or more expandable elements or balloons. The first treatmentregion 28 may thus provide a first treatment pattern or shape having asubstantially arcuate, circular, and/or circumferential orientation. Inturn, the second treatment region 38 may include a substantially linearor focal-type electrode enabling energetic or thermal exchange with acontacted tissue area to create a second treatment pattern that includesa substantially linear or “spot” configuration. The multiple treatmentpatterns obtainable through the selective and independent use of thefirst and second treatment regions allows a user the ability toadaptively create varying treatment patterns tailored to a particularpatient's anatomy and any patient-specific physiological maladies thatare being diagnosed or treated with the medical device 12.

The medical system 10 may include one or more sensors to monitor theoperating parameters throughout the system 10, including for example,pressure, temperature, flow rates, volume, or the like in the controlunit 14, and/or the medical device 12. For example, the medical device12 may further include one or more temperature and/or pressure sensors(not shown) proximate the treatment region(s) for monitoring, recordingor otherwise conveying measurements of conditions within the medicaldevice 12 or the ambient environment at the distal portion of themedical device 12. The sensor(s) may be in communication with thecontrol unit 14 for initiating or triggering one or more alerts ortherapeutic delivery modifications during operation of the medicaldevice 12.

The medical device 12 may include a handle 42 coupled to the proximalportion of the elongate body 16, where the handle 42 may include anelement such as a lever or knob 44 for manipulating the elongate body 16and/or additional components of the medical device 12. For example, apull wire 46 with a proximal end and a distal end may have its distalend anchored to the elongate body 16 at or near the distal portion 20.The proximal end of the pull wire 46 may be anchored to an element suchas a cam in communication with and responsive to the lever 44.

The handle 42 can further include circuitry for identification and/oruse in controlling of the medical device 12 or another component of thesystem 10. For example, the handle may include one or more pressuresensors 48 to monitor the fluid pressure within the medical device 12.Additionally, the handle 42 may be provided with a fitting 50 forreceiving a guide wire that may be passed into the guide wire lumen 26.

The handle 42 may also include connectors that are matable directly to afluid supply/exhaust and control unit 14 or indirectly by way of one ormore intermediary coupling components. For example, the handle 42 may beprovided with a first connector 52 and a second connector 54 that arematable with the control unit 14. The handle 42 may further includeblood detection circuitry 56 in fluid and/or optical communication withthe injection, exhaust and/or interstitial lumens. The handle 42 mayalso include a pressure relief valve 58 in fluid communication with theinjection, exhaust and/or interstitial lumens to automatically openunder a predetermined threshold value in the event that value isexceeded.

Continuing to refer to FIG. 1, the medical device 12 may include anactuator element 60 that is movably coupled to the proximal portion ofthe elongate body 16 and/or the handle 42. The actuator element 60 mayfurther be coupled to the proximal portion of the guide wire lumen 26such that manipulating the actuator element 60 in a longitudinaldirection causes the guide wire lumen 26 to slide towards either of theproximal or distal portions of the elongate body 16. As a portion ofeither and/or both the first and second expandable elements may becoupled to the guide wire lumen 26, manipulation of the actuator element60 may further cause the expandable element(s) to be tensioned orloosened, depending on the direction of movement of the actuator element60, and thus, the guide wire lumen 26. Accordingly, the actuator element60 may be used to provide tension on the expandable element(s) during aparticular duration of use of the medical device 12, such as during adeflation sequence, for example. The actuator element 60 may include athumb-slide, a push-button, a rotating lever, or other mechanicalstructure for providing a movable coupling to the elongate body 16, thehandle 42, and/or the guide wire lumen 26. Moreover, the actuatorelement 60 may be movably coupled to the handle 42 such that theactuator element is movable into individual, distinct positions, and isable to be releasably secured in any one of the distinct positions.

The second treatment region 38 may be deflectable, steerable, orotherwise manipulated into a desired position or configurationindependently or differently from the first treatment region 28 and/oradjacent portions of the elongate body 16. In particular, the elongatebody 16 of the medical device 12 may be constructed from one or morelayers of material or differing components to provide a desired degreeof flexibility while maintaining the capability to transmit torque alongthe length of the medical device 12. The layers may include a multitudeof polymers, plastics, and composites thereof, as well as braided orother structural reinforcing materials/components running therethrough.The elongate body 16 may further include one or more steering wires oractuation mechanisms to deliver a force to a particular segment orportion of the medical device 12, such as a region proximate to thesecond treatment region 38, in addition to the pull wire describedabove, which may provide deflection or steering of the first treatmentregion 28. The medical device 12 may also include a deformational ordeflectable segment 62 between the first and second treatment regionsthat aids in the manipulation of the second treatment region 38 withrespect to the first treatment region 28. For example, the deflectablesegment may include a bellows-like region, varying material thickness orbending characteristics, or other features providing ease of deflectionor movement of the second treatment region 38 with respect to the firsttreatment region 28.

In an exemplary system 10, a fluid supply 64 including a coolant,cryogenic refrigerant, or the like, an exhaust or scavenging system (notshown) for recovering or venting expended fluid for re-use or disposal,as well as various control mechanisms for the medical system 10 may behoused in the control unit 14. In addition to providing an exhaustfunction for the fluid supply, the control unit 14 may also includepumps, valves, controllers or the like to recover and/or re-circulatefluid delivered to the handle, the elongate body 16, and treatmentregion(s) of the medical device 12. A vacuum pump 66 in the control unit14 may create a low-pres sure environment in one or more conduits withinthe medical device 12 so that fluid is drawn into the conduit(s) of theelongate body 16, away from the treatment region(s), and towards theproximal end of the elongate body 16. The control unit may also includea radiofrequency signal generator or power source 68 in electricalcommunication with the electrodes 40. The control unit 14 may includeone or more controllers, processors, and/or software modules containinginstructions or algorithms to provide for the automated operation andperformance of the features, sequences, or procedures described herein.

The power source 68 may optionally provide electrical pulses to themedical device 12 to perform an electroporation procedure, as describedin U.S. patent application Ser. No. 13/194,259, filed Jul. 29, 2011, theentirety of which is hereby incorporated by reference. “Electroporation”utilizes high electric field amplitude electrical pulses to effectuate aphysiological modification (i.e., permeabilization) of the cells towhich the energy is applied. Such pulses may be short (e.g., nanosecond,microsecond, or millisecond pulse width) in order to allow applicationof high voltage without large flow of electrical current that wouldresult in significant tissue heating. In particular, the pulsed energyinduces the formation of microscopic pores or openings in the cellmembrane. Depending upon the characteristics of the electrical pulses,an electroporated cell can survive electroporation (i.e., “reversibleelectroporation”) or die (i.e., irreversible electroporation, “IEP”).Reversible electroporation may be used to transfer agents, includinglarge molecules, into targeted cells for various purposes.

Now referring to FIGS. 2-3, in an exemplary method of use, the medicalsystem 10 may be used to deliver multiple therapeutic treatment patternsto one or more targeted tissue areas 70. For example, the medical device12 may be positioned and operated to ablate targeted tissue region(s) inthe heart. The first treatment region 28 may be positioned in theproximity of a pulmonary vein opening or junction with a portion of theatrial wall. Such positioning may be aided or facilitated byvisualization methods including fluoroscopy or the like as known in theart. Where the first treatment region 28 includes an expandable element,the expandable element may be inflated or otherwise expanded tosubstantially occlude the pulmonary vein. The occlusion reduces theblood flow around the treatment region, thereby allowing enhancedthermal exchange between the medical device 12 and the targeted tissue.

Once the first treatment region 28 has been positioned where desired, itmay be operated to affect a desired therapy, such as tissue ablation.For example, the tissue ablation may be achieved by the circulation of acryogenic fluid from the source and/or control unit 14, to the elongatebody 16, and through the expandable elements of the first treatmentregion 28. The first treatment region 28 may be used to create a firsttreatment pattern on the targeted tissue, and may include asubstantially arcuate or rounded orientation around at least a portionof the pulmonary vein. Circulation of the coolant through the firsttreatment region 28 may continue until a desired amount of tissue, e.g.a volume or depth of the tissue, has been ablated or otherwise treated.The extent of the tissue freezing with the medical device 12 may beassessed or ascertained by measuring impedance on or about the medicaldevice 12 and the tissue region (using the electrodes 40 for example),by implementing visualization or imaging modalities distinguishingbetween frozen and non-frozen tissue masses, or by providing coolantcirculation under predetermined parameters (such as pressure, flow rate,delivery duration, etc.) that have previously been established asproviding the desired effect under experimental or pre-clinicalinvestigation.

Upon achieving the desired tissue freezing depth or extent, circulationthrough the first treatment region 28 may cease, the first treatmentregion 28 may be thawed either actively or passively by the surroundingblood flow, and the medical device 12 may be repositioned or otherwisemanipulated to direct the second treatment region 38 proximate to thepulmonary vein or other tissue region (FIG. 3). Such positioning mayagain be aided or facilitated by visualization methods includingfluoroscopy or the like as known in the art. In addition, coolant may bedirected into the first treatment region 28 to create a sufficiently lowenough temperature to cryoadhere the first treatment region 28 to anadjacent tissue region. Cryoadhesion may be established without allowingtemperatures of the first treatment region 28 to fall low enough tocause permanent tissue injury or unwanted ablation. The first treatmentregion 28 may thus provide an anchoring point to stabilize the distalregion of the medical device 12, thereby easing accurate placement,positioning, and/or deflection of the second treatment region 38, whichmay include the manipulation of one or more steering or deflectionmechanisms as described herein.

The second treatment region 38 may then be used to create a secondtreatment pattern different from the first, either in substantialcontinuity with the previously-created treatment pattern orindependently in another tissue region. For example, the one or moreelectrodes 40 of the second treatment region 38 may be powered tothermally affect or ablate the selected tissue. Powering of theelectrode(s) 40 may include delivery of a radiofrequency signal orcurrent from the radiofrequency source 68 resulting in a current flow,and thus heating, between one or more of the electrodes 40 eitherbetween each other (e.g., bipolar RF delivery) or to a ground/patientelectrode (not shown) in unipolar or monopolar operation. The operationof the electrodes 40 may be controllably modulated to achieve thedesired physiological affect, such as ablation. For example, theelectrodes 40 may be powered by the radiofrequency signal/power sourcesuch that the electrodes 40 are maintained at a predetermined, selectedtemperature with the power delivered to the electrodes 40 increasing anddecreasing in response to a measured temperature at or near theelectrodes 40, or based upon predetermined parameters and correlationsbetween the electrode temperature and/or electrode power delivery.

The disclosed system 10 provides a number of benefits and advantages.For example, providing multiple treatment regions with differenttreatment pattern capabilities allows a physician to tailor treatment tospecific patients, as described above. It also allows a physician oruser to create a first, larger pattern with the first treatment region28, for example, and then follow up with the second treatment region 38to create secondary, smaller patterns to fill in gaps or “touch up” thefirst treatment pattern. This may be particular convenient whenattempting to isolate or otherwise ablate an anatomical structure suchas a pulmonary vein (though other structures may be similarly treated)with a substantially continuous ablative pattern. The first treatmentregion 28 may be used to create substantially the entire desiredpattern, with the second treatment region 38 used to treat missed orincongruous regions in the intended treatment region—resulting in asubstantially continuous treatment pattern.

In addition, employing different treatment energy modalities (e.g.,cryogenic and radiofrequency or electroporation) reduces the complexityof providing independently-controllable treatment regions that areexclusively cryogenic. For example, providing two differentindependently-controllable cryogenic treatment regions would includeproviding multiple sets of independently controllable fluid paths andassociated controls (e.g., valves, regulators, or the like) in aminimally-invasive device having small dimensions and space therein,whereas a radiofrequency- or electrically-powered segment may includeone or more small-dimensioned wires that are more readily integratedinto the device. Furthermore, the independently controlled cryogenictreatment region may be used as a cryoadhesive anchor to facilitatesecure positing and placement of the distally-located radiofrequencytreatment region, as described above, which is not achievable withexclusively radiofrequency-powered devices.

It will be appreciated by persons skilled in the art that the presentinvention is not limited to what has been particularly shown anddescribed herein above. In addition, unless mention was made above tothe contrary, it should be noted that all of the accompanying drawingsare not to scale. A variety of modifications and variations are possiblein light of the above teachings without departing from the scope andspirit of the invention, which is limited only by the following claims.

What is claimed is:
 1. A medical device, comprising: an elongate catheter body including a proximal portion coupled to a handle and a distal portion; a cryogenic treatment region coupled to the distal portion of the catheter body; and at least one of a radiofrequency treatment region and an electroporation treatment region coupled to the distal portion of the catheter body at a location that is distal to the cryogenic treatment region and defining an outer surface of and a distal tip of the medical device.
 2. The medical device of claim 1, wherein the cryogenic treatment region includes an expandable element.
 3. The medical device of claim 2, wherein the at least one of a radiofrequency treatment region and an electroporation treatment region includes a substantially linear thermal segment.
 4. The medical device of claim 1, wherein the cryogenic treatment region is operable independently from the at least one of a radio frequency treatment region and an electroporation treatment region.
 5. The medical device of claim 1, further comprising a fluid flow path in fluid communication with the cryogenic treatment region.
 6. The medical device of claim 5, further comprising a cryogenic fluid source in fluid communication with the first fluid flow path.
 7. The medical device of claim 6, further comprising a radiofrequency signal source coupled to the at least one of a radiofrequency treatment region and an electroporation treatment region.
 8. The medical device of claim 1, further comprising a sensor coupled to at least one of the cryogenic treatment region or the at least one of a radiofrequency treatment region and an electroporation treatment region.
 9. The medical device of claim 1, wherein the at least one of a radiofrequency treatment region and an electroporation treatment region is deflectable independently of the cryogenic treatment region.
 10. An intravascular ablation device, comprising: a flexible elongate body including a proximal portion coupled to a handle and a distal portion; an expandable element coupled to the distal portion of the elongate body; a substantially linear, elongated radiofrequency thermal segment coupled to the distal portion of the elongate body and extending distally beyond the expandable element when the expandable element is fully expanded; a cryogenic coolant source in fluid communication with an interior of the expandable element; and a radiofrequency energy source in communication with the radiofrequency thermal segment.
 11. The intravascular ablation device of claim 10, wherein radiofrequency thermal segment includes an electrically-conductive distal tip.
 12. A method of treating cardiac tissue, comprising: positioning an expandable cryogenic treatment region proximate a pulmonary vein, the cryogenic treatment region being coupled to a distal portion of a medical device; ablating tissue proximate the pulmonary vein with the expandable cryogenic treatment region; positioning a radiofrequency treatment region proximate the pulmonary vein, the radiofrequency treatment region including an electrode coupled to distal portion of the medical device at a location distal to the cryogenic treatment region when the cryogenic treatment region is fully expanded; and ablating tissue proximate the pulmonary vein with the radiofrequency treatment region.
 13. The method of claim 12, wherein positioning the expandable cryogenic treatment region includes expanding the expandable cryogenic treatment region in the pulmonary vein to substantially occlude the pulmonary vein.
 14. The method of claim 13, wherein ablating tissue proximate the pulmonary vein with the expandable cryogenic treatment region includes circulating a cryogenic fluid through the expandable cryogenic treatment region.
 15. The method of claim 13, wherein ablating tissue proximate the pulmonary vein with the expandable cryogenic treatment region includes creating a first ablative treatment pattern, and wherein ablating tissue proximate the pulmonary vein with the radiofrequency treatment region includes creating a second ablative treatment pattern.
 16. The method of claim 15, wherein the first ablative treatment pattern includes a substantially arcuate shape.
 17. The method of claim 16, wherein the second ablative treatment pattern includes a substantially focal shape.
 18. The method of claim 17, wherein the first and second ablative treatment patterns are substantially continuous.
 19. The medical device of claim 9, wherein the medical device further comprises a deflectable segment located between the at least one of a radiofrequency treatment region and an electroporation treatment region and the expandable cryogenic treatment region, the deflectable segment facilitating deflection of the at least one of a radiofrequency treatment region and an electroporation treatment region relative to the expandable cryogenic treatment region. 